Indeed, there is a relatively easy way to force any Windows Phone to 8107 in about 15 minutes (after you get all the right files in place) and in fact, we just did it to our Samsung Focus S, mostly because we have a crap-ton of Windows Phones here and can take risks.

We're going to assume you don't have extra phones and therefore we can't really endorse this because:

Having said that, if you still want to go down this path we can say it does work and if you follow the directions to the letter, you'll have 8107 on your Windows Phone (you just won't have any "tweaked" OEM firmware to go with it).

Once again, we must stress that we're not endorsing this method and we would much rather see AT&T just deliver an update. Should you screw up your phone, this is all on you.

So against our better judgement (and Rafael's ire), we're going to post our tutorial on the subject. Read on, if you dare...

What you will need

[We should note: this tutorial assumes you're on OS build 7720] First thing you'll want to do is download the necessary files, those are the following:

WP7 Update Cab Sender

7740 update CAB file

8107 update CAB file

Language packs (see below)

Optional: WPSupport tool X86 or x64 (For those with COM problems or errors)

What we are doing is using an official Microsoft tool to back up the phone and then send the OS updates (in the form of CAB files) directly to the device. The language packs are 100% necessary and vary from device type to device type.

We can't stress this enough: getting the languages right is key to this process -- you will have issues if you have too many or too few language packs (see the earlier problems with this method) On our Focus S, we had to install all 22 language packs, which yes, was a pain namely because we had to download those all individually. If you have more than 22 language packs on your phone, do NOT do this update and stop here.

Update: The AT&T HTC TITAN only has English (United States) installed, so that is the only language pack needed. The AT&T Samsung Focus S needs all 22.

Verify your Language Packs

On your Windows Phone, go to Settings --> Region + Language and look under Display language. There you should see all the language packs installed on your phone. As we mentioned above, on our Focus S we have all 22 installed. You need to go through and check.

And by check we mean write down those languages. Alternatively, you can use the included "Version and Language by Heathcliff74.xap" (you'll need a dev unlocked phone to install) and it will list all the language packs and codes. If you only have 5 languages on your device, then you should have those 5 language packs ready. If you have 22 language packs, then use all 22.

Here are the individual languages that you need to download to the same directory as the OS install files from above:

You should now see a screen similar to the one below with device details and the proceeding backup of your phone. Next, it will install OS 7740 and OS 8107 (it needs to do both) along with the necessary language packs.

Time of install will vary, but it should be about 15 minutes (backup will be the big differentiator here). After that, your phone should restart and you'll be on 8107 with all your apps, files, photos, messages, etc. fully intact i.e. this does not wipe your device.

And that's it.

Update 2: For those with COM errors, go back to the top and download the WP Support Tool for you computer and install. That should fix it.

Reader comments

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question...
could this finally be a way to update your phone whenever you want instead of waiting for carriers to push an update?
i.e. run this following every step to a T, EXCEPT delete the update .cab files?

Just wanted to report that I updated my 1st gen Samsung Focus with this described method. It was really quite painless, but took over 20 mins because I have used up all but 500MB of the stock 8GB on the phone. Was hoping not to get a COM error and didn't. I also saw mastito's alternate method, but it seems it "debrands" your phone, and I wasn't sure if that meant that I would definitely not get any future updates from AT&T (if any were planned) or other similar repercussions. Funny though, I actually went to the website in that method beforehand, and while typing it in, the keyboard disappeared lol.

For those having Phone tile issues,
You are missing a language file. Looks like some of the Titans have more than English installed. Revert to 7720 and grab the languages cab. Unzip them all to the cab sender folder. Then run the update. No more phone tile issue!
Also, be sure to place the cab sender folder in the root of C drive. Use an elevated command prompt (Windows Vista/7/8/Win2008 Server) to start "WP7 Update Cab Sender.bat" after starting the UPDATEWP.EXE for your OS version.

Is there a way to know that my Venue Pro is officially unlocked or not, I live in Jordan (Middle East) and I'm running it on a local carrier sim card but the problem is that my software is still on 7.10.7720.68 and I really want to know how to update
it to 8017..

Dell checked my service tag and replied with :
" this unit was sold as a locked unit. It is locked to the T-Mobile network. As a rule, we don't provide unlocked codes for devices which were sold locked, but if you'd like to try sending any other questions regarding this, please email unlockcoderequest@dell.com."

so I opened the Engineering Mode in my phone and looked at the security, it was
(Unlock / GLEOS2A_US_TMO_SIMLoc1_001)
what does that mean? was it unlocked by hacking or an official unlock code? and the most important thing is will this update re-lock my phone or not?

Awesome! This updated my unlocked LG Quantum (orginally AT&T) to 8107. I had tried several times to update using the LG MFG Registry tool, but it never worked.
I nitially had a COM error, but thaat was solved with the WPSupport Tool.
Thanks WP Central!

I posted this in the http://forums.wpcentral.com/software-development-hacking/188730.htm but wanted to add as a comment to this thread too to maximize potential for responses :)
So I completed the update to 8107 yesterday on my AT&T Rev 1.3 Samsung Focus and all went smoothly, suddenly today my "phone" tile was no longer working. I figured it had to be the update as I had not changed anything else on the device so I went to restore the backup I had created yesterday when updating.
Must not be my day today because during the restore process the usb connection somehow disconnected (not physically) and I ended up with the following symptoms:
- Cannot boot my phone past the first white samsung logo coming up
- Can access download mode
- Can access Hard Reset/Format
After going through the process with either a hard reset I briefly see the Samsung Logo again on my device and then get a black screen for a minute or so. After that the windows phone logo with usb cable and pc logo showing connect the usb cable to my pc comes up and sits on the screen nothing else happens.
I have read that this may indicate that it is possible to flash my device back to the original retail rom using WP7 downloader ver 7.21 BUT I am having trouble finding/getting access to the original roms link from the xda developers site. Wondering if anyone has any other links to the original at&t retail rom for focus v1.3 or if anyone here can give me any other suggestions on fixes for the above described issue?
Thanks in advance to anyone with any suggestions!!

When running the batch file I keep running into this error - 'CHOICE' is not recognized as an internal or external command, operable program or batch file.
Did I miss something along the way or do I need to edit my batch file. I am on a XP box so I imagine that could be contributing to the issue.

Thanks WPCentral! I followed your procedure and it worked flawlessly for my year-old Samsung Focus. Beats the heck out of waiting for the next update AND for AT&T to decide if they're gonna release it.

I have Samsung focus too but for me the phone function does not work post update. Although every other application works fine but the phone and dial pad does not respond. Let me know if you faced the same issue with Samsung focus

I'm having trouble with step 5. It's working but is repeatedly asking me to 'press any key to continue'. It has created 300+ folder log entrys in the 'logs' folder and I have no idea how much longer it will take. Is there a way to do the backup in a streamed method (no prompting)?
Also, step 6 is a little vague on 'then install the updates'. How?
How do I install to the phone?

I decided to try this update on my Sprint HTC Arrive. I followed the directions and did the update on my Wife's phone (HTC Arrive) and mine with ZERO issues. Nothing was deleted, no errors, and do not see the disappearing keyboard issue (fingers crossed). Sync's fine with Zune. My wife has her own profile on this Windows 7 machine so I did the update on my profiel, then switched to her profile to complete the update of her phone. Thanks Daniel and WPCentral!

I have the HTC titan and I know that the only language pack I need is English, but i was wondering if I can add spanish as well since I will give the phone as a gift to a person that only speaks spanish.

I tried this update yesterday and it defenitly started working... but post update the "call" function stopped responding. I had to restore to 7720 :-(. If you can help i would love to manually push these updates on my phone.
The update took approx 15 mins and it showed up system info too that i have 8107. i tested by replying on few emails. everything else work except the "call" function.

I have an HTC Surround on 7720. I tried doing forcing to 8107, using the steps above and got this error:

Error: Retrieving the COM class factory for component with CLSID {77CB935D-D0CC-
4249-8643-3C387A514A27} failed due to the following error: 80040154.
Call stack:
at Microsoft.WindowsMobile.DeviceUpdate.DeviceManager.Initialize()
at Microsoft.WindowsMobile.DeviceUpdate.DeviceManager.get_Instance()
at wm7update.Program.Main(String[] args)

I tried the Windows Phone Support Tool and it said it can't recover my phone. It says "the tool cannot recover this phone. Please contact technical support." Zune software reports a restoration error. It says my phone can't be restored to the latest software restore point.
Any ideas?

I have a HTC HD7 AT&T device with 7.10,7720.68 version.
I have tried to update it using the procedure you have describrd above but after number of errors and resolutions i stuck at strange error,
==========================================
Error: The resource loader failed to find MUI file. (Exception from HRESULT: 0x8
0073AFC)
Call stack:
at wm7update.Program.UpdateDevice(IDeviceInfo deviceInfo, List`1 updates, Upd
ateType type)
at wm7update.Program.Main(String[] args)
■
╚══════» Done
Press any key to continue . . .
==========================================

Yes I get this msg to after it backs up , installs update to phone , phone reboots, then the Dos Screen says the above msg you mention Kweku. My phone also displays that the update has failed. Im on a HTC HD7 Phone with OS Version: 7.10.8773.98.

Help for the technically slow people - I followed the instructions above to update my HTC Arrive (Sprint) phone. The process ran once. When the process was completed, it still shows Windows Phone 7.5 OS Version 7.10.8107.79.
Any idea where I went wrong?

I just tried going from version 8773 (tango) to 8779, then to 8783 then to 8858, 8779 worked, 8783 failed then 8858 worked. After the update finished my phone restarted ok but no new start screen or new tiles. Also all my non MS apps stopped working and most of my settings options wouldn't open.
Any ideas what could have gone wrong? i'm in the process of trying a restore to see if i can get some functionality back....

Thank you! I tried to use Seven Eighter but it wouldn't work for the life of me. It kept saying I was missing a CAB file and when I looked it up, no such file existed. I used your method, though, and it worked like a charm.

Tried runnung the CabSender tool for my HTC Arrive, but the program got hung on the "Restarting your phone.." step. Then it reported the timeout error. Now when I'm starting the phone I'm stuck with a screen showing the phone connected to computer (on black background). I did not reach the point of creating a backup so UpdateWP /restore says "No Restore point found". Do I have any chances to cancel this installation mode and boot to my phone again?

Hard reset helped to clear the state above (maybe USB cable was loose). I actually was able to finish installation, but at the very end I've got the same error as some other people were getting before:
IU (Image Update) installation failed on phone: No applicable packages.
I've tried SevenUpdater - the same result. At least my phone was not ruined after all of that, but I still have a question - how to uprrade my HTC Arrive to Windows 7.8? What's unique for that?